Keyboard operated code transmitter



Oct. 24, 1944. R! MATHES 2,361,115

KEYBOARD OPERATED CODE TRANSMITTER Filed Feb. 5, 1942 Z SheetS-Sheet 1INVENTOR ATTORNEY Oct. 24, 1944. R MATHES 2,361,115

KEYBOARD OPERATED CODE TRANSMITTER Filed Feb. 5, 1942 Z SheetS-Sheet 2VE'N OR ATTORNEY Patented Oct. 24, 1944 KEYBOARD OPERATED CODETRANSMITTER Richard E. Mathes, Westfield, N. J., assignor to RadioCorporation of America, a corporation of Delaware Application February5, 1942, Serial No. 429,648

12 Claims. ,(Cl.178-80) This invention relates to keyboard transmittersfor telegraph systems and more particularly to a transmitter of the typewhich is adapted to transmit synchronized signals.

In ordinary start-stop keyboard transmitters no continuoussynchronization is required between the transmitting and receivingstations since the cyclic transmission of each code signal as initiatedat the transmitter is closely enough followed by the speed of operationof the receiving instrumentality. The keyboard transmitter whichconstitutes the subject matter of the instant invention, however, is onewhich transmits the code signals for each character in a predeterminedtime relation to the operation of a time division simplex or multiplexdistributor. Such a distributor may be run continuously and'a receivingdistributor can be maintained in synchronism with the transmittingdistributor by well known means.

In the synchronized signal transmission systems for which my inventionis best adapted to be used there is no provision for operating printerson the start-stop principle. For this reason transmission is normallyeffected by perforating a transmission tape with the desired signals.

- Tape perforators for this purpose have been known in the art for aconsiderable time. One embodiment of such a perforator is described in abook entitled Printing Telegraph Systems and Mechanisms by H. H.Harrison, published by Longmans, Green 8: Company. On page 167 of thisbook is a brief description of a similar known keyboard perforator,reference being made to Fig. 165 on page 166. Thatis a perforator of theso-called "Morkrumf system.

One of the disadvantages of using perforated tape for signaltransmission is that'a certain delay in' the transmission itself must ofnecessity occur after the tape has been perforated. This fact is due tothe impracticability of immediately utilizing the tape perforations fortransmission after a given portion of the tape has been punched by thekeyboard. For certain types of springs in association with a synchronousdis-1 tributor.

It is, therefore, an object of my invention to provide modifications ofa keyboard perforator such as will provide for direct transmission, notfrom the perforated tape, but from contact springs directly controlledby the keyboard.

It is another object of my invention to pro-- vide a combination ofdirect keyboard transmitter and tape perforator such that, when messageshave been transmitted by direct keyboard operation, a perforated tapeshall simultaneously have been prepared for record purposes at thetransmitting station and for repeating the messages, if necessary.

Other objects and advantages of my invention will be made apparent inthe more complete description to follow. This description is accompaniedby drawings to which reference will be made for a clearer understandingof the invention. In the drawings:

Fig. 1 shows in perspective certain component parts of a keyboardperforator and transmitter sufficient for a clear description of myinvention; and

Fig. 2 shows a circuit diagram of the connections which in a preferredembodiment of my invention are necessary to establish operatingcommunication and classes of traflic such delays I -signals by directcontrol ofcertain code contact association between a keyboardtransmitter and a synchronous transmitting distributor.

Referring to Fi 1, I show therein a key bar I!) which is only one, ofcourse, of the entire group of key bars of the keyboard. This key bar ispivoted at H and carries a code selector comb l2 which may beafiixedthereto in any suitable manner, as, for example, by rivets l3. Theselector comb may, however, be welded on if desired; or in certaininstances itmay be formed integrally with the key bar. Beneath the combI2 is an arrangement of loop bails P, andl to I inclusive. The bail P isactuated by each and every key and has the function of actuating acertain lever system which stores and locks a given set-up'of contacts,together with associated punch levers, until transmission-of theselected code signal has been effected. In the embodiment shown thefunction of the bail P is modified with respect to its normal functionin the conventional keyboard perfora'torf That normal functionheretofore has been to close a contact of a switch forelectromagnetically driv ing the punch hammer and the" tape feed deviceof the perforator. As will be hereinafter explained, the electromagnetfor actuating the punch and tape feed device according to my insprings31 are attached. 7

vention is controlled by a local circuit closed periodically at aparticular phase of rotation of the transmitting distributor.

The loop bails l to l inclusive serve when they are actuated forimmobilizing their respective punches and simultaneously for openingcorresponding contacts of the signal code composing circuits. Theseloop. bails are allpivoted on the pivot rod 9. Above this pivot rod thebails extend upwardly, these extensions being indicated 1 at M.

are of variable height, but each is notched for- Certain shoulders onthe extensions l4 engagement with a bell crank I 5. There-are seven ofthese bell cranks, each corresponding with one of the elements of a'Z-uriit codesignal. They areall mounted on a'vertical pivot'rod l6. Onthis same pivot rod is also mounted a lever arm 26 which engages with anotch in the ve'r-f tical extension 21 operable from and -by the.

. pointedly beyond the linkage centers ll. These pointed ends arearranged to be engaged by. a wedge-shaped member 28 which is movableforwardly and backwardly in order to provide a lock forstoring theset-up of each signal until after it has been transmitted.

The forward ends of the bell cranks are pivotally connected at H tocontrol armslB which extend within the assembly consisting of a die andstripper plate, punch block, guide plate, shedder, and shedder wearingstrip, shown generally at IS. The details'of construction of thisassembly are not herein described. since they are well known in the art.e 7

According. to .my invention the conventional loop bail extensions 14 arestill tfurther extended in vertical portions =29 all of which reach anequal height. At the top of each extension 29 and bearing against thebackedge thereof are irisulation blocks 38 supported by contact springs3 ton which is normally pressedintocontact with a bus bar 32. This bus.bar- 32 is connected with a contact33 (as shown in Fig. 2) and, when anyvcombination of thebell cranks is actuated,

connection isn ade between the contact 33 and acontact spring 34. .Thelatter is-supplied with signalling energyfrom any'suitable source, hereindicated as the positive terminal of such a source, the negativeterminal being vunderstood to be grounded. Actuation of the spring 34 isobtained by pressureof a pluralityof bell cranks I5 against the verticalactuating bar 35. When this bar is not actuated current is suppliedthrough the contact 34 tothree back contacts 36 whichare used fortransmission of a blank? signal. This signal is not used for typewriterspacing, but fills in the signalling time of the transmittingdistributor whenever the keyboard operator fails to actuate his 1 keysin step with the distributor. This'conditio will ice-discussedhereinafter.

The wedge-shaped member 28 terminates above and below inabackwardgextension to which These springs 'are drawn rearwardly byattachment to the pivot rod H3. The member 28 is also Suitably held inplace byguides (not shown) but it is free toislide for-;

moving levers-39 in a direction to drive the wedgeward and backward. Thesprings 3! tend to pull it backwardly.

I have also provided sets of levers 38 and 39 for the purpose of forcingthe member 28 into its forward position. Lever 38 is pivoted at 40,whereas lever 39 is pivoted at 4!. The punch hammer 2| is ofconventional construction. The lever 38 is arranged with'a: forwardlyprojecting hook 38a sothat when 'the punch hammer 2| is moved forwardlylever 38 will rotate though a small angle about the pivot center 40,thereb;

member 28 forwardly and out of engagement with the pointed ends of thebell cranks l5. Although) the .retu rnXback) stroke of the punchhammer12'l "follows its forward stroke immediately upon deenergizationof the operating magnetiZi, I have arranged to lock the wedge-member.28. forwardly in dependence upon deenergization of the punch hammermagnet 25 and to unlock thewedge-member 23 in dependence upon asubsequent actuation .of a keylllu- The mechnism foraccomplishing-this.includes lever arms 26 and 42, the latter beinghorizontally pivoted-at 43. One end of the lever 42 is tapered and fitsunder the lever,25. The other end of lever 42 has ashoulder on the'undersideto fit over the end of the backward extension 28a which isintegralwith the wedge-member 28. It will be" clear from the perspectiveview'of F-ig. 1 that priorto a. key depression the back edge of theeXtensiOnZila will rest in. the recess under the end'of leverf'42."This'forward end of lever 42 is raised upon key depression, at whichtime bail Poperatesft'o move lever 26 against the tapered slope at theback end of lever 42; Then the springsjSl'areallowedto'contract, thusdraw- Each contact spring-3| hasacontact but- 1 mg the wedge member 28backwardly into en'- gagem'ent with'the pointed ends of the bell cranks15. This looks thesebell'cranks' in whichever position they have beensetby key depression. Unlocking takes place 'only' after thewedgememberzll has been removed (forwardly) from engagementjwiththe bellcrank levers, that is, upon actuation .of thepunchjmagnetzh At thismoment the forward end of lever 42 is allowed to drop by gravity(aidedby a" spring if desired) so that the underlyingshoulder near theend of this lever will engagewith th'eback edge 'of the extension 23a.This. engagement locks the wedge-member 28 in its forward position ofdisengagement with thejbellcranks "untilsuch time as a'subsequent key isdepressed.

' In the operation of "inyinvention a message to be transmitted 'is bothperforated on the tape 58 and is caused'to set up -code combinations'foreach depression of oneof the keys In of the keyboard.- According (to the7 unit code system, which'is preferably used in connection with'mykeyboard transmitter, each key depression causes three and?onlythree'holes to be 'punched in the tapeby withdrawing selected ones;fo'ur in number, of the levers fll from the' p'ath of the punch lever 2lopposingres'pective punches with: in the punch block assembly lm I Eachkey when depressed selects for actuation suitable ones of the bails I tolinclusive, four in number, not only-to'actuate the' bell cranks l5, butalso to-openfour selectedcontacts on-the springs.3.-|,leaving.tonlyathree' of these in engagement with thebus bar- 32h-Tlie actuation of the extension pieces'ZHIOn the-upstandingextensionsI4 for codeccomposing purposes hasalreadybeenexplained; 7* .1

In Fig. 2 it .Will beobserived-i that each :or the contact springs 3| isconnected directly or indirectly with certain segments 5| of a rotarydistributor. The distributor itself is shown in developedform.Associated with the segments 5| is abus ring 52 which is connected totransmitting equipment of any suitable type, such asa keying circuit fora radio transmitter. Assuming that the brush 53 rotates at apredetermined transmission speed as controlled by synchronizingimpulses, the code combinations will obviously be collected bypassage ofthis brush 53 successively over the respectivev segments 5|. Thus, eachcode combination will be immediately trans. mitted upon depression ofits appropriate key.

The operation of the keyboard to perforate the tape is also performed ina conventional manner. In order to permit the transmission of a.suc-,cession of code impulses substantially without ine terruption it isnecessary to store at least a portion of each code signal in a storagedevice'such as shown at 54. The details of this storage device are notherein given since reference may be made to a similar storage devicedescribed inan application of James A. Spencer, Serial No. 357,109,filed September 17, 1940, now Patent No. 2,327,075, granted Aug.,1'7,1943. Reference is here made to Fig. 1 of that application for showinghow a part of the code signal may be electromagnetically stored andsubsequently transmitted in proper sequence with respect to the codeelements for which direct connections are made between the transmittingcontacts and the distributor.

In conformity with Spencers system aforementioned, I show individualcircuits between contacts 3| and the first four segments of thedistributor ring 5| (Fig. 2), while the remaining contacts 3| areconnected to the windings of appropriate storage relays (not shown) inthe device 54. These relays are locked up automatically upon completingtheir operating circuits through the contacts of a timing relay undercontrol of an impulse from source 51 through bus ring 55 and segments(12 and d3 which feed conductor 59 when swept over by brush 56. The samestorage relays possess contacts through which impulses are transferredto the 5th, 6th, and 7th segments of distributor ring 5|, for completingthe transmission of each code combination. At the commencement of thenext revolution of the brush 55, a clearing relay (not shown) isactuated for unlocking the three storage relays. This actuation takesplace upon passage of brush 56 over segment (11. It will thus be seenthat these relays constitute means for introducing a hang-over ofeffects produced by the closing of the contacts 3| so that the code barsoperated by the keys l0 may be returned to normal and the contacts 3|opened even before the brush 53 has traversed the segments5| connectedtothe storage device 54.

The actuation of the punch magnet 25 is accomplished by means of a localcircuit closed by brush 56 passing over segments ds and d6, thisfunction being thus timed to follow the scanning of the code elements asset up on the contacts 3|. The code signals are thus perforated in thetape while they are being transmitted to the keying circuit.Furthermore, the operation of the punch hammer 2| causes thewedge-member 28 to be driven into a position of disengagement from thepointed ends of the bell cranks I5. The bell cranks are then free to berestored to normal positions. A subsquent key depression causes anothercombination of hell cranks l5 to be moved across the apex of thewedge-member 28, and

since the-latter is also release'dby lever '-42, the bell cranksarelocked in their actuated positions until the next energization of thepunch magnet 25.

Should the operator depress two keys within a single 'cycle of thedistributor, it is truethat an improper signal might be transmitted.Such a'signal, however, would contain more than three marking elements,and, in accordance withthe prevailing practice in the-use of a7-unitcode signal system, such erroneous signal would be indicated by anerror indication. All correct-signals will be understood. therefore, toconsist of three marking elements. .v

For continuous sending the keyboard must be operated in cadence with thelocal pulses through the brush 56 andsegment-55-of the distributoriHowever, as this is difficult for operators and re-' quires highlyspecialized training, I h'avepro vided for a blank signal to betransmitted wheneverthe operator skips a beat of the op eratingmagnet25. This is the purpose of the threecontacts 36 which engage with thecontact spring 34'. When the contact spring '34 engages with contacts 35no current is supplied to the bus bar 32; hence in the-absence of-keydepression a code signal consisting ofthree elements in the fifth,sixth, and seventh positions, for example, will be transmittedthroughcontacts36 and associated segments 5| of the distributor. Thereceiving printer performs nooperatingfunction when this blank signalis-received, butth fact that the signal is composed of three markingunits permits the error detector to count it as correctly received andtherefore no error designating symbol will be printed as would be thecase upon reception of a mutilated signal. f

It will, of course, be understood by those skilled inthe art thatmodifications'of my invention may be made without departing from thespirit.

thereof.

I- claim:

1. A keyboard-operated code signaling device having in combination, aset of keys arranged in a keyboard, a tape perforator having codepunches selectively operable under control of the keyboard keys, meansincluding a continuously driven transmitting distributor for timing theoperation of punching code elements in a tape and for suc-' cessivelytransmitting the several code "elements of each character signalselected by said keys, a plurality. of contact devices arranged forselective actuation by said keys in accordance with code signals to betransmitted, and in agreement with the code elements to be punched'insaid tape,'and' means for causing the code elementsof each signal to bepunched in said tape during the time occupied in transmitting the samesignal from said contact devices through said distributor to a telegraphchannel.

2. The method of utilizing the keyboard or a 4 permutations of holes tobepunched' in a tape, locking means. operable upon each key depressionlforl momentarily storing successive settings :of

said selective means, continuously operable distributormeans foreffecting :successiveutransmission of; the codegelements ofveach,signal-, lmeans electrically in circuit .withsaid distributormeans and. Operable under control of said key.-

bars and bails forcomposing vthexcode elements of each signal, and meansa periodically operable by said distributor-.meanslfor causing eachsignal permutation so, ,cornposed to be transmitted through saiddistributor. and :for: simultaneously perforating the code elements ofthe samesignal insaid tape. a.

4.-In-a keyboard transmitter, a group of code element contactorsnormally held infmarking positions and selectively settable to spacingpositions in accordance with the spacing units of a code signal, anassembly of keys, keybars, code element bails selectively operable-bythe keybars,and lever mechanism for selectively setting said contactors,acontinuously operable distributor having segments corresponding to saidcontactors, means for efiectingthe transmission of a code signal throu hsaid contactors and said distributor'segmentsin response to theactuation of an appropriate key, and. tape perforator means settable bysaid keys and operable'in cyclic accord with said signal transmittingmeans for storing in tape a code' -combination of perforationscorresponding with the marking elements of the transmitted signal.

5,111 atransmitter of thetype d efinedby claim 4, means operable by thekeys of the keyboard for locking selected ones of said contactors inopen dence with the cyclic operation of said distributor,

for transmitting a .blank signal through said distributor. 1 t f 7 In atelegraph system which requires the use of, a keyboard operated tapeperforatorzand a transmitting distributor having segmentsicorrespending.to the code elements of thesignals and other segments serving torhythmically control the operations of the system, the method whichcompiiseslrunning said distributor continuously, manipulating .the keysof the keyboard to set up each combination of .code elements-accordingto selected characters, causing certain. impulses-representinga portionof each said code combination to be sent out from appropriate segmentsof said distributor, momentarily storing another portion of. said codecombination and. causing the impulses thereof tobe likewise sent outfrom appropriate segments of said distributor, causing an impulsethrough at least one of said operationcontrollingsegments to actuate.the perforator thereby to punch holes in the ,tapecorresponding to thecode signal then being transmitted, and

8..I n.a keyboard-controlled system fortrahsmittinguniform lengthcharacter signals through permutationally selected contacts and throughcorresponding segments :of. a continuously operable distributor, andiorsim'ultaneously perforating. a tape in accordance with said charactersignals,- the method which comprises manipulating t e keys of saidkeyboard, causing such manipulation .tomomentarily store the codeelements of each successive character signal, causing 'the transmissionof saidsignals to. be timed by the cyclic operation of said distributor,causing the storage. of said code elements to cease at a particularcyclic phase of operation of said distributor; and effecting theperforation of each code vsignal'in said tape in'cyclic accord with theelectrical transmission of the same code signal. 9.'A keyboard-operatedcode signaling device havingimeans for permutationally punching holes ina tape and for feeding said tape across a punching position, mechanismfor momentarily storing a condition representing a permutationalset-upxof code elements to be punched in said tape'corresponding to acharacter selected by key actuation, a transmitting distributor havingcontinuously driven brushes and segments corresponding to the codeelements, contact devices for feeding a signal potentialto selected onesof said segments and thence through a first one of said brushes to acommunication channel, locking means for maintaining each code set-upduring a period commencing with the actuation of a selected key andincluding the passage of said brush over predeterminedones of saiddistributor segments, storage means connected to theremaining segmentsand actuable priorto the sweeping of said brush thereover for producinga hang-over of said code set-up beyondthe maintenance period of saidlocking means, and means including local circuits closeable by a secondone of said brushes for performing a punching operation on said tape andfor subsequently terminating the effective period'of said locking means.

10-;In combination, a keyboard-operated code composingmechanism, a tapeperforator having punches selectable by said mechanism, a set ofcode-element contacts selectively closeable by said mechanism, acontinuously operable distributor through which circuits individual tothe code elements of a character signal are successively connected to aline, and periodic timing means operable in synchronism with saiddistributor for causing selected punches of said perforator to perforatea tape, thereby to record the selected" code element combinationssimultaneously with the signal transmission thereof.

11. The combination according to claim 10 and including a plurality ofblankf-signal-composing contacts and means for causing the same to beeffective for-transmitting a, blank signal whenever the operationof saidcode composing mechanism ceases to be maintained in step with saiddistributor.

-12. The-combination according to claim 10 and including relays incertain of said code element circuits; said relays constituting meansfor introducinga hang-over of effects of'said code composing mechanismafter the latter has been restored to normal.

' RICHARD E. MA'IHES.

